In various fluid flow systems, it is important to measure parameters, such as, pH, chlorine, dissolved oxygen and ozone. In fluid flow systems, such as, wastewater treatment plants and chemical treatment plants, it is preferable to take measurements, without interrupting the system. Prior approaches for measuring such parameters include inserting sensors into the fluid flowing system but logistical issues arose as to the mounting of these sensors. In addition, measurement issues related to the variable pressures and flow rates of the system arose. Lastly, multiple components would be mounted at separate locations, but this could be very costly and time consuming.
Historically, pH measurements of a fluid have been monitored by obtaining a sample of the fluid and submerging a pH indication tape or an electrochemical sensor into the sample. Analyses of parameters such as pH chlorine, dissolved oxygen and ozone are sensitive and need to be handled properly. Removing the fluid from the sampling line and exposing it to air changes the composition of the fluid. In the case of using a pH probe, the probe generates an electrical signal that is converted into meaningful pH values by an appropriate electronic processor and those values are displayed on a meter. The probe sensor calibration process includes checking and calibrating the electronic processor to display the desired value for each buffer solution.
Furthermore, electrochemical sensors have long been used to measure parameters of fluids. Such sensors typically include a measuring electrode assembly and a reference electrode assembly, both which are electrically coupled to an instrument that senses the difference in electrical potential between the electrodes. In sensors of this kind, the measuring electrode assembly typically is exposed directly to the target fluid, either batch testing a grab sample or continuously using a flow cell that directs the fluid flow to the sensor.
In many conventional flow cells, a fluid stream continually flows past the sensor to a waste outlet. However, pressure and flow velocity fluctuations can cause errors. Conventional flow cells do little to facilitate consistent, accurate sensor output by eliminating the potential for pressure or flow changes in the fluid stream. Additionally, the fluid parameters may change when sampled and exposed to the air.
It should be appreciated that there remains a need for an integrated flow cell that addresses these concerns. The present invention fulfills this need and others.